1. Field of the Invention
The disclosure of Japanese Patent Application No. 2010-051801 filed on Mar. 9, 2010, including the specification, drawings and abstract is incorporated herein by reference in its entirety.
2. Description of the Related Art
In an internal combustion engine such as a diesel engine or the like, a diesel particulate filter (hereinafter referred to as a DPF) that collects particulate matter is arranged in an exhaust passage to remove particulate matter (hereinafter referred to as PM) from the exhaust gas discharged by the internal combustion engine. According to the related art (see, e.g., Japanese Patent Application Publication No. 2005-344619 (JP-A-2005-344619)), when there is a great discrepancy between the PM deposition amount of the DPF that is calculated based on the differential pressure across the DPF and the PM deposition amount of the DPF calculated by integrating the PM discharge amount calculated from an operation state of the internal combustion engine, it is determined that there is an abnormality in the DPF.